Method to control multiple radio access bearers in a wireless device

ABSTRACT

A method to control multiple radio access bearers is performed at a mobile wireless communication device when the mobile wireless communication device is connected to a radio network subsystem in a wireless communication network by first and second bidirectional radio access bearers. The mobile wireless communication device transmits a data packet on an uplink of the first bidirectional radio access bearer to the radio network subsystem. When the data packet is not correctly received by the radio network subsystem, the mobile wireless communication device retransmits the data packet repeatedly. After N retransmissions of the data packet, the mobile wireless communication device releases the first bidirectional radio access bearer while maintaining the second bidirectional radio access bearer. The first bidirectional radio access bearer provides a channel to transport packet switched data, and the second bidirectional radio access bearer provides a channel to transport circuit switched data.

TECHNICAL FIELD

The described embodiments relate generally to wireless mobilecommunications. More particularly, a method is described for controllinga connection having multiple radio access bearers between a mobilewireless communication device and a wireless communication network.

BACKGROUND OF THE INVENTION

Mobile wireless communication devices, such as a cellular telephone or awireless personal digital assistant, can provide a wide variety ofcommunication services including, for example, voice communication, textmessaging, internet browsing, and electronic mail. Mobile wirelesscommunication devices can operate in a wireless communication network ofoverlapping “cells”, each cell providing a geographic area of wirelesssignal coverage that extends from a radio network subsystem located inthe cell. The radio network subsystem can include a base transceiverstation (BTS) in a Global System for Communications (GSM) network or aNode B in a Universal Mobile Telecommunications System (UMTS) network.Newer mobile wireless communication devices can include the capabilityof providing several different communication services simultaneously,such as a voice call and data internet browsing at the same time. Aseparate radio access bearer can be used to transport radio link signalsfor each of the services between the mobile wireless communicationdevice and one or more radio network subsystems in the wireless network.From the perspective of a user of the mobile wireless communicationdevice, each of the communication services transported over the separateradio access bearers can be considered independent, and thereforechanges to a connection through one radio access bearer should impactminimally connections using a separate radio access bearer. Certaincommunication protocols, such as the 3^(rd) Generation PartnershipProject (3GPP) UMTS specifications, can treat a multiple radio accessbearer connection as a single connection, resulting in multiple serviceschanged together rather than separately.

Data usage through wireless communication networks has increasedsubstantially with the introduction of advanced mobile wirelesscommunication devices. As the number of data users has increased, thewireless communication networks can incur congestion and schedulingissues that affect the delivery of data to the mobile wirelesscommunication device. In some situations, a mobile wirelesscommunication device connected simultaneously by a voice connection anda data connection can continue to receive voice signals when no data oracknowledgements are received from the network. The mobile wirelesscommunication device can be configured to retransmit, reset andultimately terminate the radio link with the wireless communicationnetwork when the data connection appears unrecoverable. Terminating theradio link, however, can remove both the data connection and the voiceconnection, even though the voice connection can be operating properly.

Thus there exists a need to control multiple radio access bearersbetween a mobile wireless communication device and one or more radionetwork subsystems in a wireless communication network that releasesconnections independently.

SUMMARY OF THE DESCRIBED EMBODIMENTS

The described embodiments relate generally to wireless mobilecommunications. More particularly, a method is described for multipleradio access bearers between a mobile wireless communication device andone or more network subsystems in a wireless communication network.

In one embodiment, a method to control multiple radio access bearers isperformed at a mobile wireless communication device when the mobilewireless communication device is connected to a wireless communicationnetwork. Initially, the mobile wireless communication device isconnected to a radio network subsystem in the wireless communicationnetwork by first and second bidirectional radio access bearers. Themobile wireless communication device transmits a data packet on anuplink of the first bidirectional radio access bearer to the radionetwork subsystem. When the data packet is not correctly received by theradio network subsystem, the mobile wireless communication deviceretransmits the data packet repeatedly. After N retransmissions of thedata packet, the mobile wireless communication device releases the firstbidirectional radio access bearer while maintaining the secondbidirectional radio access bearer. In an embodiment, the firstbidirectional radio access bearer provides a channel to transport packetswitched data, and the second bidirectional radio access bearer providesa channel to transport circuit switched data.

In a further embodiment, a mobile wireless communication deviceincluding a wireless transceiver to transmit and receive from a radionetwork subsystem in a wireless communication network signals and aprocessor coupled to the wireless transceiver is described. When themobile wireless communication device is connected to the radio networksubsystem by a first radio access bearer and a second radio accessbearer simultaneously, the processor is arranged to execute a set ofinstructions. The set of instructions include transmitting a data packeton an uplink of the first radio access bearer to the radio networksubsystem and retransmitting the data packet when the data packet is notcorrectly received by the radio network subsystem. The set ofinstructions also include releasing the first radio access bearer whilemaintaining the second radio access bearer after N retransmissions ofthe data packet. In another embodiment, the set of instructions furtherinclude transmitting a reset packet on the uplink of the first radioaccess bearer to the radio network subsystem, retransmitting the resetpacket when the reset packet is not correctly received by the radionetwork subsystem, and after M retransmissions of the reset packet,releasing the first radio access bearer while maintaining the secondradio access bearer.

In another embodiment, computer program product encoded in a computerreadable medium for controlling a mobile wireless communication deviceconnected to a radio access system in a wireless communication networkby a plurality of wireless channels simultaneously is described Thecomputer program product includes non-transitory computer program codefor transmitting a data packet on a first wireless channel in theplurality of wireless channels to the radio access system. The computerprogram product further includes non-transitory computer program codefor retransmitting the data packet when the data packet is not correctlyreceived by the radio access system and non-transitory computer programcode for, after N retransmissions of the data packet, disconnecting thefirst wireless channel while maintaining a connection of at least oneother wireless channel in the plurality of wireless channels to theradio access system.

In a further embodiment, a method for controlling at least twosimultaneous wireless connections between a mobile wirelesscommunication device and a wireless access network is described. Themethod includes, at the mobile wireless communication device,transmitting and receiving circuit switched data over a first wirelessconnection, while simultaneously transmitting and receiving packetswitched data over a second wireless connection. The method furtherincludes determining by the mobile wireless communication device whetherthe transmitted packet switched data is received correctly by thewireless access network. The method additionally includes disconnectingthe second wireless connection while retaining the first wirelessconnection with the wireless access network when the transmitted packetswitched data is not received correctly by the wireless access networkafter multiple retransmissions by the mobile wireless communicationdevice.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and the advantages thereof may best be understood byreference to the following description taken in conjunction with theaccompanying drawings.

FIG. 1 illustrates a mobile wireless communication device located withina wireless cellular communication network.

FIG. 2 illustrates a hierarchical architecture for a wirelesscommunication network.

FIG. 3 illustrates a communication protocol stack for a mobile wirelesscommunication device.

FIG. 4 illustrates a multiple radio access bearer wireless connectionincluding circuit and packet switching.

FIG. 5 illustrates a data packet transmission sequence withre-transmission between user equipment (UE) and a radio networksubsystem (RNS).

FIG. 6 illustrates a data packet transmission sequence from a UE to anRNS with a disconnection of the link between the UE and the RNS.

FIG. 7 illustrates a data packet transmission sequence from a UE to anRNS with a packet data protocol deactivation.

FIG. 8 illustrates a method for controlling a multiple radio accessbearer connection between a mobile wireless communication device and awireless communication network.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

In the following description, numerous specific details are set forth toprovide a thorough understanding of the concepts underlying thedescribed embodiments. It will be apparent, however, to one skilled inthe art that the described embodiments may be practiced without some orall of these specific details. In other instances, well known processsteps have not been described in detail in order to avoid unnecessarilyobscuring the underlying concepts.

FIG. 1 illustrates a wireless communication network 100 of overlappingwireless communication cells to which a mobile wireless communicationdevice 106 can connect. Each wireless communication cell can cover ageographic area extending from a centralized radio network subsystem.The mobile wireless communication device 106 can receive communicationsignals from a number of different cells in the wireless communicationnetwork 100, each cell located at a different distance from the mobilewireless communication device. In a second generation (2G) wirelesscommunication network, such as a network following a Global System forMobile Communications (GSM) protocol, the mobile wireless communicationdevice 106 can connect to a radio network subsystem in the wirelesscommunication network 100 using one radio link at a time. For example,the mobile wireless communication device 106 can be connected initiallyto a radio network subsystem (RNS) 104 in a serving cell 102. The mobilewireless communication device 106 can monitor signals from radio networksubsystems in neighbor cells. The mobile wireless communication device106 can transfer its connection from the radio network subsystem 104 inthe serving cell 102 to a radio network system 108 in a neighbor cell110 as the mobile wireless communication device moves within thewireless communication network 100. In a third generation (3G) wirelesscommunication network, such as a network based on a Universal MobileTelecommunication System (UMTS) protocol, the mobile wirelesscommunication device 106 can be connected to one or more radio networksubsystems simultaneously through multiple radio access bearers. Each ofthe radio access bearers can transport a different communication serviceindependently, such as a voice service on one radio access bearer and adata service on a second radio access bearer. The mobile wirelesscommunication device 106 can be connected by multiple radio accessbearers simultaneously to the radio network subsystem in the servingcell 102 (if the RNS 104 supports such a connection). The mobilewireless communication device can also be connected by a first radioaccess bearer to the RNS 104 in the serving cell 102 and to a second RNS108 in the neighbor cell 110 simultaneously. Advanced mobile wirelesscommunication devices, sometimes referred to as “smart” phones, canprovide a diverse array of services to the user using a connection withmultiple radio access bearers.

FIG. 2 illustrates a UMTS wireless communication network 200 includingUMTS access network elements. The mobile wireless communication device106 operating in the UMTS wireless communication network 200 can bereferred to as user equipment (UE) 202. (Wireless mobile communicationdevices 106 can include the capability of connecting to multiplewireless communication networks that use different wireless radio accessnetwork technologies, such as to a GSM network and to a UMTS network;thus the description that follows can also apply to such “multi-network”devices as well.) In a UMTS wireless network, the UE 202 can connect toone or more radio network subsystems (RNS) 204/214 through one or moreradio links 220/222. The first RNS 204 can include a radio accesssystem, known as a “Node B” 206, which transmits and receives radiofrequency signals and a radio network controller (RNC) 208 that managescommunication between the “Node B” 206 and the core network 236.Similarly the second RNS 214 can include Node B 210 and RNC 212. Unlikea mobile wireless communication device 106 in a GSM network, the UE 202in the UMTS network can connect to more than one radio network subsystemsimultaneously. Each RNS can provide a connection for a differentservice to the UE 202, such as a voice connection through a circuitswitched voice network and a data connection through a packet switcheddata network. Each radio link 220/222 can include one or more radioaccess bearers that transport signals between the UE 202 and therespective RNS 204/214. Multiple radio access bearers can be used forseparate services on separate connections or for supplementing a servicewith additional radio resources for a given connection.

The core network 236 can include both a circuit switched domain 238 thatcan carry voice traffic to and from an external public switchedtelephone network (PSTN) 232 and a packet switched domain 240 that cancarry data traffic to and from an external public data network (PDN)234. Voice and data traffic can be routed and transported independentlyby each domain. Each RNS can combine and deliver both voice and datatraffic to mobile wireless communication devices. The circuit switcheddomain 238 can include multiple mobile switching centers (MSC) 228 thatconnect a mobile subscriber to other mobile subscribers or tosubscribers on other networks through gateway MSCs (GMSC) 230. Thepacket switched domain 240 can include multiple support nodes, referredto as serving GPRS support nodes (SGSN) 224, that route data trafficamong mobile subscribers and to other data sources and sinks in the PDN234 through one or more gateway GPRS support nodes (GGSN) 226. Thecircuit switched domain 238 and the packet switched domain 240 of thecore network 236 can each operate in parallel, and both domains canconnect to different radio access networks simultaneously.

The UMTS wireless communication network 200 illustrated in FIG. 2 cansupport several different configurations in which the UE 202 connectsthrough multiple radio access bearers to the wireless communicationnetwork. In a first configuration, a “soft” handoff of the UE 202 canoccur between the first RNS 204 and the second RNS 214 as the UE 202changes location within the UMTS wireless communication network 200. Afirst radio access bearer through the first RNS 204 can be supplementedby a second radio access bearer through the second RNS 214 beforedeactivating the first radio access bearer. In this case, multiple radioaccess bearers can be used for enhancing a connection's reliability, andthe UE 202 can typically be using one service through the multiple radioaccess bearers. In a second configuration, the UE 202 can connectthrough the first RNS 204 to the packet switched domain 240 to support apacket data connection and simultaneously connect through the second RNS214 to the circuit switched domain 238 to support a voice connection. Inthis case, the UE 202 can maintain a different radio access bearer foreach service. In a third configuration, a single RNS can supportmultiple radio access bearers to the same UE 202, each radio accessbearer supporting a different service. For the second and thirdconfigurations, it can be preferred that the establishment and releaseof each radio access bearer be independent as they can be associatedwith different services simultaneously.

FIG. 3 illustrates a layered protocol stack 300 with which a UE 202 canestablish and release connections with the UMTS wireless communicationnetwork 200 through an exchange of messages. Higher layers 310 in thelayered protocol stack 300, such as a session management layer, canrequest a connection of the UE 202 to the wireless communication network200. The connection request from the session management layer can resultin a series of discrete packetized messages known as radio resourcecontrol (RRC) service data units (SDU) passed from an RRC processingblock 308 in layer 3 of the protocol stack 300 to a radio link control(RLC) processing block 306 in layer 2 of the protocol stack 300. A layer3 SDU can represent a basic unit of communication between layer 3 peersat each end of the communication link. Each layer 3 RRC SDU can besegmented by the RLC processing block 306 into a numbered sequence oflayer 2 RLC protocol data units (PDU) for transmission over acommunication link. A layer 2 RLC PDU can represent a basic unit of datatransfer between layer 2 peers at each end of the communication link.Layer 2 RLC PDUs can be transmitted through additional lower layers inthe layer protocol stack 300, namely a media access control (MAC) layer304 that maps logical channels 314 into transport channels 312 and aphysical layer 302 that provides a radio link “air” interface. At thereceiving end of the communication link (not shown), the layer 2 RLCPDUs can be reassembled by another RLC processing block to form acomplete layer 3 SDU to deliver to another RRC processing block.

The layer 2 RLC protocol can be configured to operate in an acknowledgedmode to provide reliable transport of the layer 2 PDUs over a noisytransmission channel, such as a wireless communication link. If a layer2 PDU is lost during transmission or incorrectly received, the layer 2PDU can be retransmitted before reassembling the complete layer 3 SDU.The layer 2 RLC protocol can use an automatic repeat request (ARQ)function to trigger retransmissions. A transmitting layer 2 RLCprocessing block 306 can receive a status report from a receiving layer2 RLC processing block. The status report can be sent in response to apoll from the transmitting end or can be automatically sent by thereceiving end. Polling of the receiving end can be accomplished bysetting a polling bit in a field of a transmitted layer 2 PDU. Forexample, when a polling bit can be set in a layer 2 PDU having the lastsequence number for a particular layer 3 SDU. The layer 2 processingblock at the receiving end can recognize the polling bit and respond tothe poll by indicating the highest sequence number layer 2 PDU in thelayer 3 SDU for which all layer 2 PDUs equal to or earlier than thehighest sequence number have been correctly received. Alternatively, thereceiving end can automatically send a status report when a layer 2 PDUis received out of sequence or incorrectly received, thus alerting thetransmitting end that a layer 2 PDU has been lost or corrupted duringtransmission. The transmitting end can respond to the status report byretransmitting any missing layer PDUs. The segmentation and reassemblyfunction with error checking in the RLC layer 2 processing block 306 canensure that layer 3 RRC SDUs are transmitted and received completely andcorrectly.

As illustrated in FIGS. 2 and 4, a UMTS network can include two distinctdomains, a circuit switched domain 238 to carry circuit switched traffic(such as voice or transparent data) and a packet switched domain 240 totransport packet data (such as internet connectivity or voice over IP).As shown in FIG. 4, the UE 202 can be simultaneously connected to thecircuit switched domain 238 by a radio access bearer 402 to carry voicetraffic and to the packet switched domain 240 through a radio accessbearer 404 to carry data traffic. A radio access bearer can beconsidered a channel to transport a circuit switched data stream or apacket switched data stream between the UE 202 and the core network 236through the RNS 204. The core network 236 can set characteristics ofeach radio access bearer including data rate and quality of servicebased on requirements for the data stream transported and on a user'ssubscription among other criteria. A packet data protocol (PDP) context406 can provide a packet data connection between the UE 202 and thegateway GPRS support node (GGSN) 226 to support the exchange of internetprotocol (IP) packets using the radio access bearer 404 over thewireless access network portion of the connection. The PDP context 406can include a PDP address, such as an IP address, for the UE 202. ThePDP context 406 can be activated by the UE 202 at the session managementlayer 310, and the radio access bearer 404 can be established andassociated with the PDP context 406 to transport data for the UE 202.Once established, data can be sent as a series of layer 3 SDUs, eachlayer 3 SDU transported through numbered sequences of layer 2 PDUs asdescribed above for FIG. 3.

FIG. 5 illustrates a successful transmission of a layer 3 SDU as aseries of layer 2 PDUs including a retransmission of one of the layer 2PDUs. As shown in FIG. 5, an exchange 500 of layer 2 PDUs between the UE202 and the RNS 204 to transport a layer 3 SDU that includes eightdistinct layer 2 data PDUs can occur. Each layer 2 data PDU in the layer3 SDU can include a unique sequence number (SN). The first two layer 2data PDUs 502/504 having sequence numbers 1 and 2 can be receivedcorrectly at the RNS 204, but the third layer 3 data PDU 506 havingsequence number 3 can be lost or corrupted during transmission. When thefourth layer 2 data PDU 508 with sequence number 4 is received correctlyat the RNS 204, the RLC layer 2 processing block 306 in the RNS 204 canrecognize that the layer 2 data PDU 508 is received out of sequence. Inresponse to this sequence error, the RNS 204 can send a layer 2 statusPDU 510 that contains information about the sequence number of the lastlayer 2 data PDU in the current layer 3 SDU for which all layer 2 dataPDUs (up to and including the last layer 2 data PDU) are receivedcorrectly. Thus, for the sequence 500 shown in FIG. 5, the layer 2status PDU 510 can indicate that sequence numbers 1 and 2 have beenreceived correctly and that sequence number 3 has been lost. (Layer 2data PDU 508 with sequence number 4 has been received correctly but notlayer 2 data PDU 506 with sequence number 3, so the layer 2 status PDU508 with sequence number 4 is not yet acknowledged.) Before the UE 202receives the layer 2 status PDU 510 indicating a missing layer 2 PDU,the next layer 2 data PDU 512 in sequence can be sent. After receivingthe layer 2 status PDU 510, the UE 202 can realize that the layer 2 dataPDU 514 was lost or corrupted in transmission and resend the layer 2data PDU 514 with sequence number 3. The layer 2 data PDU 514 caninclude a poll bit enabled. Rather than send additional layer 2 dataPDUs, the UE 202 can await a response to the polling from the RNS 204.After receiving the layer 2 data PDU 514 with the set poll bitcorrectly, the RNS 204 can send a second layer 2 status PDU 516indicating that all data PDUs up to and including sequence number 5 havebeen correctly received. (The retransmitted layer 2 PDU with sequencenumber 3 filled the gap. The RNS 204 can respond with the highestsequence number, not necessarily the sequence number of the layer 2 PDUthat included the poll bit enabled.) The UE 202 can proceed to send theremaining layer 2 data PDUs 518/520/522 in the layer 3 SDU to the RNS204. The final layer 2 data PDU 522 with sequence number 8 can alsoinclude a poll bit enabled so that the UE 202 can know that the RNS 204received all of the layer 2 PDUs in the layer 3 SDU correctly. Inresponse to receiving the layer 2 data PDU 522 with the poll bit set,the RNS 204 can send a layer 2 status PDU 524 that indicates that alllayer 2 data PDUs up to and including sequence number 8 have beenreceived correctly. As shown in FIG. 5, layer 2 status PDUs can be sentin response to polling by the UE 202 or can be self triggered by the RNS204. In addition to polling when the last layer 2 data PDU in an SDU issent, the UE 202 can also poll at the expiration of a poll timer, basedon the status of one or more transmission buffers, periodically, orusing other local criteria.

FIG. 6 illustrates the UE 202 attempting unsuccessfully to send a shortlayer 3 SDU that includes two layer 2 data PDUs with no responsesreceived by the UE 202 from the RNS 204. The UE 202 sends a first layer2 data PDU 602 in the layer 3 SDU with sequence number 1 followed by asecond layer 2 data PDU 604 with sequence number 2, where the secondlayer 2 data PDU 604 includes a poll bit set. While the RNS 204 receivesthe first layer 2 data PDU 602 correctly, the second layer 2 data PDU604 is not received correctly by the RNS 204. Slow responses or noresponse from the RNS 204 in the wireless network to the UE 202 canoccur when congestion and scheduling issues arise for a number ofreasons. For example, the number of users accessing data connections andthe amount of data traffic transported can overwhelm the planned andallocated network capabilities. Initially the UE 202 can retry sendingthe last layer 2 data PDU 04 if the wireless network appears to bestalled. The UE 202 can set a poll timer when sending the last layer 2data PDU 604 having the poll bit set, and after a first poll timeinterval 606, the UE 202 can resend the last layer 2 data PDU 604 againwith the poll bit set. The UE 202 can reset the poll timer, and uponexpiration of the poll timer, the UE 202 can resend the last layer 2data PDU 604. This polling can repeat up to a maximum number of pollsspecified by a parameter MAX DAT provided by the wireless network whenestablishing the radio access bearer that supports the data connectionbetween the UE 202 and the RNS 204. As shown in FIG. 6, each of therepeated layer 2 data PDU 604 transmissions can be lost or incorrectlyreceived by the RNS 604.

After polling the RNS 204 MAX DAT times, the UE 202 can begin a reset ofthe RLC layer 2 connection between the UE 202 and the RNS 204. The UE202 can send an RLC layer 2 reset PDU 614 to the RNS 204 and can waitfor an RLC layer 2 reset acknowledgement PDU from the RNS 204. If nolayer 2 acknowledgement PDU is received within a first reset timerinterval 616, the UE 202 can resend the RLC layer 2 reset PDU 614 to theRNS 204. After resending the RLC layer 2 reset PDU 614 MAX RESET times,the UE 202 can conclude that the RLC layer 2 connection is unable to berecovered. The UE 202 can disconnect 622 the link between the UE 202 andthe wireless network by changing from an active connected state to anidle state, thereby releasing the layer 3 RRC connection. Subsequentlythe UE 202 can send a cell update 624 control message to the wirelessnetwork indicating the state change due to an RLC layer 2 unrecoverableerror. (The cell update message can be sent on a common control channelbetween the UE 202 and the wireless network that is separate from theunrecoverable data connection.) By entering the idle state, the UE 202can disconnect both the data connection experiencing unrecoverableerrors on one of the radio access bearers and also any other data orvoice connections that can be simultaneously using separate radio accessbearers. Thus, a user of the UE 202 can experience a dropped voice calldue to an unrelated data stall on a simultaneous data connection whenconnected through multiple radio access bearers.

FIG. 7 illustrates an alternative method for controlling the UE 202 whenconnected to a wireless network by multiple radio access bearers thatcan disconnect an errant data connection while maintaining othersimultaneous connections of the UE 202 to the wireless network. As inFIG. 6, the UE 202 can send a layer 3 SDU to the RNS 204 as two separatelayer data PDUs 602/604 each with distinct sequence numbers. The secondlayer 2 data PDU 604 (and last layer 2 data PDU in the layer 3 SDU) caninclude a poll bit enabled, and the UE 202 can repeatedly send the lastlayer 2 data PDU 604 MAX DAT times when no acknowledgement is receivedfrom the RNS 204. After MAX DAT polls, the UE 202 can start a deactivatetimer, and at the expiration of a deactivate time interval 704, the UE202 can deactivate 706 the packet data protocol (PDP) context associatedwith the data connection that is not responding. As a result ofdeactivating the PDP context, the associated radio access bearer can bereleased by the wireless network without affecting connections throughother radio access bearers between the UE 202 and the RNS 204. The UE202 can thus release radio resources, just as when a user of the UE 202can end a data connection or voice call independently of each other,without entering an idle state that can disrupt multiple simultaneousconnections of the UE 202 to the wireless network. The length of thedeactivate time interval 704 can be set so that the PDP contextdeactivation 706 occurs during a deactivate time period 702 between theend of polling and the end of sending the layer 2 reset PDUs. The UE canavoid disconnecting the radio link 622 by not changing to the idle stateas done in FIG. 6.

Generalizing from the method illustrated in FIG. 7, FIG. 8 outlines amethod for controlling a multiple radio access bearer connection betweena mobile wireless communication device and a wireless communicationnetwork. The mobile wireless communication device can transmit a datapacket using a first radio access bearer in step 802. The mobilewireless communication device can determine if the data packet isreceived correctly by the wireless communication network in step 804.When the data packet is received correctly, the method can terminate.When the data packet is not received correctly, then in step 806, themobile wireless communication device can determine if the data packethas been retransmitted an integer N number of times. If less than Nretransmissions have occurred, then the mobile wireless communicationdevice can repeat the transmitting and determining steps 802, 804 and806. After N retransmissions without the data packet being receivedcorrectly by the wireless communication network, the mobile wirelesscommunication device can release the first radio access bearer on whichthe data packets are transmitted in step 816, while simultaneouslymaintaining a second radio access bearer between the mobile wirelesscommunication device and the wireless communication network in step 820.In step 808, the mobile wireless communication device can optionallywait for a deactivation time period before releasing the first radioaccess bearer. Additional optional steps also provide for transmitting areset packet after the N data packet retransmissions. In step 810, thereset packet can be transmitted by the mobile wireless communicationdevice to the wireless communication network. The mobile wirelesscommunication device can determine if the reset packet is receivedcorrectly by the wireless communication network in step 812. When thereset packet is received by the wireless communication network correctlythe method can terminate. If the reset packet is not received correctly,then the mobile wireless communication device can determine if the resetpacket has been retransmitted an integer M number of times. If less thanM retransmissions have occurred, then the mobile wireless communicationdevice can repeat the transmitting and determining steps 810, 812, and814. After M retransmissions the mobile wireless communication devicecan release the first radio access bearer while maintaining the secondradio access bearer.

Various aspects of the described embodiments can be implemented bysoftware, hardware or a combination of hardware and software. Thedescribed embodiments can also be embodied as computer program code on acomputer readable medium for configuring a mobile wireless communicationdevice. The computer readable medium is any data storage device that canstore data which can thereafter be read by a computer system. Examplesof the computer readable medium include read-only memory, random-accessmemory, CD-ROMs, DVDs, magnetic tape and optical data storage devices.The computer program medium can also be distributed over network-coupledcomputer systems so that the computer readable code is stored andexecuted in a distributed fashion.

The various aspects, embodiments, implementations or features of thedescribed embodiments can be used separately or in any combination. Theforegoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the invention.However, it will be apparent to one skilled in the art that the specificdetails are not required in order to practice the invention. Thus, theforegoing descriptions of specific embodiments of the present inventionare presented for purposes of illustration and description. They are notintended to be exhaustive or to limit the invention to the precise formsdisclosed. It will be apparent to one of ordinary skill in the art thatmany modifications and variations are possible in view of the aboveteachings.

The embodiments were chosen and described in order to best explain theprinciples of the invention and its practical applications, to therebyenable others skilled in the art to best utilize the invention andvarious embodiments with various modifications as are suited to theparticular use contemplated.

1. A method, comprising: at a mobile wireless communication device,wherein when the mobile wireless communication device is connected to aradio network subsystem in a wireless communication network by a firstbidirectional radio access bearer and a second bidirectional radioaccess bearer simultaneously, transmitting a data packet on an uplink ofthe first bidirectional radio access bearer to the radio networksubsystem; retransmitting the data packet when the data packet is notcorrectly received by the radio network subsystem; after Nretransmissions of the data packet, transmitting a reset packet on theuplink of the first bidirectional radio access bearer to the radionetwork subsystem; retransmitting the reset packet when the reset packetis not correctly received by the radio network subsystem; and after Mretransmissions of the reset packet, waiting for a deactivation timeperiod before releasing the first bidirectional radio access bearerwhile maintaining the second bidirectional radio access bearer.
 2. Themethod as recited in claim 1, wherein the first bidirectional radioaccess bearer provides a channel to transport packet switched data, andthe second bidirectional radio access bearer provides a channel totransport circuit switched data.
 3. The method as recited in claim 1,wherein the data packet is a layer 2 data protocol data unit and thereset packet is a layer 2 reset data protocol unit.
 4. The method asrecited in claim 3, wherein the layer 2 data protocol data unit includesa poll bit enabled, thereby requesting an acknowledgement from the radionetwork subsystem that the layer 2 data protocol data unit is correctlyreceived.
 5. A mobile wireless communication device, comprising: awireless transceiver arranged to transmit to and receive from a radionetwork subsystem in a wireless communication network signals overmultiple radio access bearers; and a processor coupled to the wirelesstransceiver, the processor arranged to execute instructions for: whenthe mobile wireless communication device is connected to the radionetwork subsystem by a first radio access bearer and a second radioaccess bearer simultaneously, transmitting a data packet on an uplink ofthe first radio access bearer to the radio network subsystem;retransmitting the data packet when the data packet is not correctlyreceived by the radio network subsystem; after N retransmissions of thedata packet, transmitting a reset packet on the uplink of the firstbidirectional radio access bearer to the radio network subsystem;retransmitting the reset packet when the reset packet is not correctlyreceived by the radio network subsystem; and after M retransmissions ofthe reset packet, waiting for a deactivation time period beforereleasing the first radio access bearer while maintaining the secondradio access bearer.
 6. The mobile wireless communication device asrecited in claim 5, wherein the first radio access bearer provides achannel to transport packet switched data, and the second radio accessbearer provides a channel to transport circuit switched data.
 7. Themobile wireless communication device as recited in claim 5, wherein thedata packet is a layer 2 data protocol data unit and the reset packet isa layer 2 reset data protocol unit.
 8. The mobile wireless communicationdevice as recited in claim 7, wherein the layer 2 data protocol dataunit includes a poll bit enabled, thereby requesting an acknowledgementfrom the radio network subsystem that the layer 2 data protocol dataunit is correctly received.
 9. Computer program product encoded in anon-transitory computer readable medium for controlling a mobilewireless communication device connected to a radio access system in awireless communication network by a plurality of wireless channelssimultaneously, the computer program product when executed by computerperforming steps comprising: transmitting a data packet on a firstwireless channel in the plurality of wireless channels to the radioaccess system; retransmitting the data packet when the data packet isnot correctly received by the radio access system; after Nretransmissions of the data packet, transmitting a reset packet on thefirst wireless channel to the radio access system; retransmitting thereset packet when the reset packet is not correctly received by theradio access system; and after M retransmissions of the reset packet,waiting for a deactivation time period before disconnecting the firstwireless channel while maintaining a connection of at least one otherwireless channel in the plurality of wireless channels to the radioaccess system.
 10. The computer program product as recited in claim 9,wherein the first wireless channel transports packet switched data, andat least one other channel in the plurality of wireless channelstransports circuit switched data.
 11. The computer program product asrecited in claim 9, wherein the data packet is a layer 2 data protocoldata unit and the reset packet is a layer 2 reset data protocol unit.12. The computer program product as recited in claim 11, wherein thelayer 2 data protocol data unit includes a poll bit enabled, therebyrequesting an acknowledgement from the radio access system that thelayer 2 data protocol data unit is correctly received.
 13. A method forcontrolling at least two simultaneous wireless connections between amobile wireless communication device and a wireless access network, themethod comprising: at the mobile wireless communication device,transmitting and receiving circuit switched data over a first wirelessconnection; transmitting and receiving packet switched data over asecond wireless connection; determining whether the transmitted packetswitched data is received correctly by the wireless access network; anddisconnecting the second wireless connection after waiting for adeactivation time period while retaining the first wireless connectionwith the wireless access network when the transmitted packet switcheddata is not received correctly by the wireless access network after Nretransmissions of the packet switched data by the mobile wirelesscommunication device, and after M retransmissions of a reset packet whenthe reset packet is transmitted on the second wireless connection to thewireless access network and is not correctly received by the wirelessaccess network.
 14. The method as recited in claim 13, furthercomprising: resetting the second wireless connection before thedisconnecting of the second wireless connection.